Evaluate the integrals for $f(x)$ shown in the figure below. $($Note that the graph of $f(x)$ is made up of two semicircles.$)$

$($Give exact answers.$)$

a$){\displaystyle \underset{0}{\overset{2}{}}}2f(x)dx=$ I$\_$

b$){\displaystyle \underset{0}{\overset{6}{}}}2f(x)dx=$

c$){\displaystyle \underset{1}{\overset{4}{}}}5f(x)dx=$

d$){\displaystyle \underset{1}{\overset{6}{}}}|5f(x)|dx=$